We are attempting to develop systems for cloning and introducing genes into mosquito germ lines. In addition we are attempting to define factors which render mosquitoes refractory to malarial infection. Special emphasis is being placed on the genetics of Anopheles gambiae as it relates to Plasmodium falciparum, the primary vector/parasite combination in sub-Saharan Africa. Concurrently, a simian malaria, P. cynomolgi is being used as a model for these studies. Mode of inheritance and the physiological basis for refractories is being studied in one selected strain of An. gambiae.